The star identified as KSN 2011a is almost 300 times the size of our sun and 700 million light years from Earth while star KSN 2011d is 500 times bigger than the sun and well over a 1 billion light years away.

They analyzed light captured by Kepler every 30 minutes over a three-year period from 500 galaxies and 50 trillion stars.

“To see something that happens on timescales of minutes, like a shock breakout, you want to have a camera continuously monitoring the sky,” said Garnavich. “You don’t know when a supernova is going to go off, and Kepler's vigilance allowed us to be a witness as the explosion began.”

Garnavich’s research team, Kepler Extragalactic Survey or KEGS is almost finished compiling data from Kepler’s primary mission which looked for supernovae - the death explosions of stars.

The Kepler mission ended prematurely in 2013 following a technical failure, but NASA's K2 mission is now searching even more galaxies for supernova events.